Double detent mechanism



June w, 1958 L. J. PATLA DOUBLE DETENT MECHANISM Filed Aug. 12, 1955INVENTOR.

para. BY-

MN .v W

Unite 2,837,933 Patented June 10, 1958 DUUBLE DETENT MECHANISM Louis J.Patla, Elmwood Park, Ill.

Application August 12, 1953, Serial No. 373,843

6 Claims. (Cl. 74-627) This invention relates to a double detentmechanism and to a television tuner switch employing such a doubledetent mechanism. it is an object of the invention to provide improvedapparatus of that character.

In view of the prospective use of additional television channels, somein the ultra high frequency range, it is desirable that the basic tuningswitch of television sets have more than the customary twelve positionsor settings, preferably twice that number. Normally, some form of detentmechanism is employed whereby the movable switch element snapssuccessively into these positions or settings as the operator turns theswitch to tune the television set to different channels. However, asimple detent mechanism having twenty-four positions must necessarily beobjectionably large in diameter. For example, in a ball type detentmechanism, if the ball and the various detents are to be of substantialsize, in order to give smooth and positive action, they must besubstantially removed from the axis of the rotary switch parts in orderto obtain a large circle of travel. Such a large detent mechanism isobjectionable in television sets because of the already crampedquarters.

According to one embodiment of the present invention, only twelvepositions are provided in the basic detent mechanism and a second detentmechanism is provided by which the relatively stationary plate of thefirst detent mechanism may be pivoted through an angle which is equal toone and one-half times the angle between the various positions providedfor by the first detent mechanism. lt will readily be seen that if thefirst or basic detent mechanism provides for movement of the movableswitch element to various positions separated by 30, movement of therelatively stationary plate of the detent mechanism through an angle of45 will permit movement of the switch element to a series of positionslying intermediate the adjacent switch positions obtainable prior toshifting of the said detent plate. Through this means, twenty-fourpositions of the switch arm become available while using a basicdetentmechanism which provides for movement of the switch arm through steps of30.

A detent mechanism constructed in accordance with the invention permitsthe selection of any one of a large number of switch positions eventhough both elements of the detent mechanism are small in diameterwhereby the basic or principal detent mechanism, which is old in .theart, permits the selection or" only a small number of switch positions.

Accordingly, it is another object of the invention to provide animproved detent mechanism which is small in size and, particularly,small in diameter and which still permits smooth, positive positioningof a controlled device in any one of a large number of positions.

Where a double detent mechanism constructed in accordance with theinvention is applied to a television tuning switch, for example, thepositions of the switch as controlled by the primary or basic detentmechanism, with the second detent mechanism in one given position,

may be positions corresponding to the V. H. F. channels,

'2,721,'9 11, both by the present inventor. construction of the tuningswitch proper does not of itwhile another set of switch positionspermitted by the primary detent mechanism when the secondary detentmechanism is in a second position, may be positions corre sponding toU.H. F. channels. A suitable index on the second detent mechanism mayindicate V. H. F. and U. H. F. in its respective positions, whereby theselection and indication of V. H. F. and U. H. F. channels is simpliliedand clarified Accordingly, it is another object of the invention toprovide an improved tuning switch assembly for a television set.

It is another object of the invention to provide improved double detentmechanism which may select two or more times the number of positions forthe controlled element as any previously known detent mechanism of thesame diameter. it is another object of the invention to provide animproved television tuner switch incorporat ing such a double dctentmechanism therein.

This invention, together with further objects and advantages thereof,will best be understood by reference to .the following description takenin connection with the accompanying drawing, in the appended claims.

In the drawing, in which like parts are designated by likereferencenumerals,

Fig. 1 is an exploded perspective View of television set tuning switchapparatus illustrating one embodiment of the invention;

Fig. 2 is an elevational view of the rotary switch element incorporatedin the tuning switch of Fig. 1; and

'Fig. 3 is a diagram illustrating the various selectable positions ofthe tuning switch madepossible by the double detentmechanismincorporated in the tuning switch assembly of Fig. l.

The television tuning switch assembly illustrated in Fig. 1 includes atthe right-hand end a tuning switch proper ill. This switch includes asubstantially cupshaped base '22 secured to rods 13 which form a part ofthe frame of the assembly. Stationary contact supports 14 are mounted onthe back of the cup-shaped member 12, these supports extending throughan opening 15 in the cup-shaped member 12 to support stationary contactsin desired positions within the cup-shaped member.

Also arranged within the cup-shaped member 12 is a rotary switch member16, see Fig. 2, lating plate 17 upon which are mounted a series ofcontacts 18 and a series of tuning coils 19, see Fig. 1. It will and itsscope will be pointed out be noted that the insulating plate 3.7 isslotted at its center ;placed in the tuning circuits to tune thetelevision set to different channels. Preferably, two coils or centertapped coils are arranged on each of twelve coil bases to permit greaterconcentration of the necessary tuning coil construction. The tuningswitch proper may be, and prefer- ,ably is, constructed in accordancewith the inventions disclosed and claimed in application Serial No.139,229, entitled Multiple Contact Switch,'filed January 18, 1950,

now Patent No. 2,682,645, and application Serial No.

189,458, entitled Electrical Apparatus and Method of Making Same, filedOctober 10, 1950, now Patent No. Since the actual self-constitute afeature of the present invention, and since a suitable switch mechanismis described in the aboveidentified applications, it will not bedescribed in further detail herein.

To the left of the tuning switch 11 there is a primary comprising aninsudetent mechanism 21. This includes a ball plate 22 ,Which is slottedto receive the operating shaft 20. Two

detent balls 23 cooperate with the ball plate 22 and are caused torotate therewith, upon turning of the operating shaft, through theirengagement with respective holes 24 in the plate 22. The holes 24 aresubstantially smaller than the balls 23, whereby the balls cannot passthrough the holes but are retained in a fixed position with respect tothe plate 22.

A detent plate 25 is provided having a series of protrusions 26 whichdefine intermediate depressions 27. It will be seen that the alternateprotrusions 26 and depressions 27 are arranged in a circle of suchdiameter that as the ball plate 22 is caused to rotate with respect tothe detent plate 25, the balls 23 must ride over the protrusions 26 andsnap successively into the intermediate depressions. If it be assumedthat the detent plate 25 is held stationary, it will be seen that theball plate 22 tends strongly to snap into various definite angularpositions with respect to the detent plate 25. Similarly, the shaft 20and hence the rotary contact member 16 also tend to settle intopredetermined angularly displaced positions.

A second detent mechanism 31 employs a ball plate 32 and balls 33,similar to the ball plate 22 and the balls 23, the ball plate 32 beingprovided with holes 34 which are smaller than the cooperating balls 33but large enough to cause the balls 33 to rotate with the ball plate 32.

A detent plate 35 is provided which is secured to a portion of the frameof the over-all assembly. The detent plate 35 has arranged thereon pairsof protrusions 36 and intermediate protrusions 36' which definedepressions 37. It will be understood that the balls 33 ride over theintermediate protrusions 36' and snap into depressions 37 at either sidethereof. The protrusions 36 are of such height that the balls 33 cannotride thereover, whereby in the illustrated embodiment of the inventionthe ball plate 32 may occupy either one of only two operating positions.

It will be seen that screws 38 are provided by which the ball plate 32may be secured to the detent plate 25, the screws 38 passing throughslots 32' in the ball plate 32 and into threaded openings 25' in thedetent plate 25.

The ball plate 32 is securely mounted on an operating shaft 40 which isactually a tube surrounding an intermediate portion of the operatingshaft 20. A suitable handle 41 is secured to the shaft 40 and a handle42 is secured to the shaft 20.

The angular displacement of the pairs of depressions 37 in the detentmechanism 31 is made equal to 45 in the illustrated embodiment of theinvention. The angular displacement of adjacent depressions 27 in thedetent to snap successively into the angular positions designated by theindices a -a in Fig. 3.

If the control knob 41 is now rotated to cause the ball plate 32 of thedetent mechanism 31 to snap into its alternate position, the ball plate32, the entire detent mechanism 21, the shaft 20, and the rotary switchelement 16 are all caused to rotate through an angle of 45 Accordingly,the same movable contact which might have been in the position a ismoved to a position indicated by the index b Subsequent rotation of thecontrol knob 42 will cause that same rotary contact to snap successivelyinto the various positions indicated by the further indices b --b In theillustrated application of the double detent mechnism, namely, theapplication to a television set tuning switch, the switch 11 when in thepositions corresponding to the indices a a might tune the set to V. H.F. channels, and the switch in the positions corresponding to theindices b b may tune the set to U. H. F. channels. In such case asuitable indicator mounted on the tubular shaft 40 or on the operatinghandle 41, not shown in the drawing, can be arranged to indicate V. H.F. and U. H. F. in the respective positions of the handle 41. Suitableindicia can be associated with handle 42 to indicate channels 1-12, andintermediate such indicia another set of indicia may be provided forindicating U. H. F. channels. If the handle 41 were then turned to itsV. H. F. position, rotation of the handle 42 would result in successiveindicating of channels 1-12, the corresponding indicia and the tuningswitch skipping over the U. H. F. settings. Conversely, if the handle 41were turned to its U. H. F. position, rotation of the handle 42 wouldresult in the tuning switch 11 and the indicia associated with thetuning handle 42 assuming positions corresponding to the successive U.H. F. settings and skipping over the V. H. F. settings.

In the illustrated embodiment of the invention the secondary detentmechanism 31 has been arranged to snap through an angle of 45 ratherthan through an angle of 15, either of which would result in effectivelyshifting the movable switch contacts through 15. If the secondary detentmechanism 31 is in such position that the control handle 42 permitsselection of any one of the positions corresponding to the indices el-r1 of Fig. 3, shifting of the secondary detent mechanism 31 through anangle of 15, 45 or 75 will permit the control handle 42 to move the samemovable switch contacts only to positions corresponding to the indices b---b of Fig. 3.

A 45 shift is preferable over a 15 shift in the detent mechanism 31,since the 45 shift permits larger and more definite protrusions 36 withcorrespondingly lighter spring pressure whereby the operation of thisdetent mechanism may be smoother and its centering action more positive.Obviously the forces which center the detent mechanism 31 in itspositions must be superior to the forces operating in the primary detentmechanism 21 whereby rotation of the handle 42 in either direction willnot cause operation of the detent mechanism 31.

The rotary switch member 16 of the illustrated embodiment hastwenty-four pairs of contacts 18 u may be seen in Fig. 2. It will benoted that alternate pairs 18a of contacts are arranged on a pair ofconcentric circles and that the intermediate pairs 18b are arranged ondifferent concentric circles. Two sets of stationary contacts (notshown) are arranged on the contact supports 14, one set so arranged asto engage the contacts 18a (and the other set arranged to engage thecontacts 18b. The stationary contacts are spaced apart by an angle of30, whereas the angle of displacement of adjacent pairs of movablecontacts 18a and 18b is 15. Accordingly, when the handle 41 is in oneposition the movable contacts 18a may come to rest in engagement withcooperating stationary contacts while the contacts 18b come to rest insuch positions that they do not contact the other set of stationarycontacts. Conversely, when the handle 41 is in its other position, thecontacts 18b cooperate successively with the other pair of stationarycontacts while movable contacts 18a come to rest in positions whereinthey do not electrically contact any stationary contacts.

In the illustrated embodiment of the invention, any given pair ofcontacts 18a may be connected to a V. H. F. tuning coil whereas anadjacent pair of movable contacts 18b is connected to a U. H. F. tuningcoil which placed from each other by an angle of 40.

termediate the positions previously available.

disc 17and only twelve basic coil constructions .19 need be provided.

In the illustrated applicatijn of the detent mechanism or in otherapplications, it may be desired that the sec ondary detent mechanism 31be provided with three or more angularly displaced positions. This canbe accomplished by providing additional protrusions 36' andcorresponding additional depressions 37. The angle of displacement inthe prim-ary detent mechanism and in the secondary detent mechanism mustof course be of such values as to result in different angular positionsof the device-controlled by the overall detent mechanism. For example,if the primary detent mechanism is as suggested in the previouslydescribed embodiment of the invention, wherein it permits centering ofthe controlled device in twelve positions angularly displaced by 30, thethree position secondary detent mechanism would opcrate satisfactorilyit its adjacent positions were dis- Then when the secondary detentmechanism moves from its first position to its second position, theeffective shifting of the controlled device would be 4030, or Move-.ment of the secondary detent mechanism to its third position, 80 fromits original position, would result in an efiective shift of SSW-60, orThe controlled device would then have three sets of twelve positions,the :twelve positions of any one set being selectable by operation ofthe primary detent mechanism, and the choice ofthe three sets ofpositions being selectable by operation of the secondary detentmechanism. An arrangement such as that suggested immediately above wouldbe desirable in an application in which the three sets of positions ofthe controlled device had some distinguishing characteristiccorresponding to the two V. H. F. and U. H. F. settings of the secondarydetent mechanism 31 of the illustrated embodiment of the invention.

The illustrated embodiment of the invention employs two detentmechanisms in series with each other to the advantage that a primarydetent mechanism may be of a given small size and may permit selectionof any one of a given small number of angularly displaced positions of acontrolled device. At the same time, the total number of positions ofthe controlled device is doubled or trebled by arranging a secondarydetent mechanism in series with the primary detent mechanism, thesecondary detent mechanism shifting the entire primary detentmechanism-as well as the controlled device through such an angle thatthe positions of the controlled device, now selectable by the primarydetent mechanism, lie in- This invention therefore permits the'selectionof any one of a large number of positions of a controlled device whileemploying a small, smoothly operating detent mechanism, which lattercharacteristics are inherent in a detent mechanism having a small numberof selectable positions.

Furthermore, the present invention divides the total number of positionsof the controlled device into groups, one group of positions beingavailable by operation of one control handle when a secondary controlhandle is in one position, and the second group of positions beingavailable by operation of the first control handle when the secondaryhandle is in another position. This characteristic of the invention isparticularly desirable where the total number of positions of thecontrolled device may be divided into logical groups.

By way of example other than that illustrated in the drawing anddescribed above, when the control handle 41 is in one position,operation of the control handle 42 may be caused to close successivecircuits whereby temperature indications may be obtained, and with thecontrol handle 41 in a second position, operation of the control handle42 may be caused to close successive circuits whereby pressureindications may be obtained.

It is to be noted that the rotatable member of either U or both of thedetent mechanisms may carry the protrusions 26 or 36 and inte mediatedepressions defined thereby while the relatively stationary member maycontrol the balls 23 or 33. Also various forms of detent mechanismsother than the illustrated ball type (many f which are known) may beused without departing from the spirit of the invention. Furthermore,the movable member 32 and the relatively stationary member 25 may be oneintegral element rather than two members secured together, and where twosuch members are specitie-d herein it is to be understood that suchlanguage is to be interpreted to include a single integral elementserving two functions, one in connection with each of the two detentmechanisms.

Accordingly, while a particular embodiment of the invention has beenshown, it will be understood, of course, that the invention is notlimited thereto since many modifications may be made, and it is,therefore, contemplated to cover by the appended claims any suchmodifications as fall within the true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured by Letters Patent is:

1. A detent mechanism comprising a relatively stationary base member anda rotatable member connected to a load element, said rotatable memberand its load element being movable to center said load element in anyone of a plurality of angularly displaced positions with respect to saidbase member, a second detent mechanism comprising a fixed member and arelatively rotatable member movable to any of at least two angularlydisplaced positions with respect to its fixed member, said base memberor" the first detent mechanism being connected to and rotatable withsaid relatively rotatable member of the second detent mechanism, theangular displacement of said relatively rotatable member in movingbetween saidpositions being other than the angular displacement betweenpositions of said load element, and said second detent mechanism beingself-maintained in set position during operation of said first detentmechanism, whereby the positions of said load member due to rotation ofits connected rotary member may be increased by movement of saidrelatively rotatable member from one position to another.

2. In a switch construction having a rotary switch element, a detentmechanism comprising a relatively stationary base member and a rotatablemember connected to said switch element, said rotatable member and itsswitch element being movable to center said switch element in any one ofa plurality of angularly displaced positions with respect to said basemember, a second detent mechanism comprising a fixed member and arelatively rotatable member movable to any of at least two angularlydisplaced positions with respect to its fixed member, said base memberof the first detent mechanism being connected to and rotatable with saidrelatively rotatable member of the second detent mechanism, the angulardisplacement of said relatively rotatable member in moving between saidpositions being other than the angular displacement between positions ofsaid switch element, and said second detent mechanism beingself-maintained in set position during operation of said first detentmechanism, whereby the positions of said switch element due to rotationof its connected rotary member may be increased by movement of saidrelatively rotatable member from one position to another.

3. A detent mechanism comprising a relatively stationary base member anda rotatable member connected to a load element, said rotatable memberand its load element being movable to center said load element in anyone of a plurality of positions angularly displaced with respect to saidbase member by a constant angle, a second detent mechanism comprising afixed member and a relatively rotatable member movable to any of atleast 12W? angularly displaced positions with respect to its fixedmember, said base member, rotatable member, load element and relativelyrotatable member being axially aligned, said base member of the firstdetent mechanism being connected to and rotatable with said relativelyrotatable member of said second detent mechanism, the angulardisplacement of said relatively rotatable member in moving between saidpositions being other than the angular displacement between positions ofsaid load element, and said second detent mechanism beingself-maintained in set position during operation of said first detentmechanism, whereby the positions of said load member, due to rotation ofits connected rotary member may be increased by movement of saidrelatively rotatable member from one position to another.

4. A detent mechanism comprising a relatively stationary base member anda rotatable member connected to a load element, said rotatable memberand its load element being movable to center said load element in anyone of a plurality of positions angularly displaced with respect to saidbase member by an angle X, a second detent mechanism comprising a fixedmember and a relatively rotatable member movable to any of at least twoangularly displaced positions with respect to its fixed member, saidbase member, rotatable member, load element and relatively rotatablemember being axially aligned, said base member of the first detentmechanism being connected to and rotatable with said relativelyrotatable member of said second detent mechanism, the angulardisplacement of said relatively rotatable member in moving between itssaid positions being equal to an odd, integral multiple of one-half X,and said second detent mechanism being self-maintained in set positionduring operation of said first detent mechanism, whereby the positionsof said load member due to rotation of its connected rotary member maybe increased by movement of said relatively rotatable member from oneposition to another.

5. In a double detent construction having a pair of concentricshafts'with the inner shaft projecting beyond one end of said outershaft, 2. first detent mechanism comprising a relatively stationary basemember mounted on said outer shaft and a rotatable member connected to aload element, both mounted on the exposed end of said inner shaft, saidrotatable member and its load element being movable upon rotation ofsaid inner shaft to center said load element in any one of a pluralityof angular displaced positions with respect to said base member, asecond detent mechanism comprising a fixed member and a relativelyrotatable member mounted on said outer shaft and movable to any of atleast two angularly displaced positions with respect to its fixed memberupon rotation of said outer shaft, the angular displacement of saidrelatively rotatable member in moving between said positions being otherthan the angular displacement between positions of said load element,control handles on said inner and outer shafts for independentlyrotating said shafts, and said second detent mechanism beingself-maintained in set position during operation of said first detentmechanism, whereby the positions of said load member due to rotation ofsaid inner shaft may be increased by movement of said relativelyrotatable member from one position to another.

6. In a switch construction having a pair of concentric shafts with theinner. shaft projecting beyond one end of said outer shaft and having arotary switch element thereon, a first detent mechanism comprising arelatively stationary base member mounted on said outer shaft and arotatable member connected to said switch element and mounted on theexposed end of said inner shaft, said rotatable mamber and its switchelement being movable upon rotation of said inner shaft to center saidswitch element in any one of a plurality of angular displaced positionswith respect to said base member, a second detent mechanism comprising afixed member and a relatively rotatable member mounted on said outershaft and movable to any of at least two angularly displaced positionswith respect to its fixed member, the angular displacement of saidrelatively rotatable member in moving between said positions being otherthan the angular displacement between positions of said switch element,control handles on said inner and outer shafts for independentlyrotating said shafts, and said second detent mechanism beingself-maintained in set position during operation of said first detentmecahnism, whereby the positions of said switch member due to rotationof said inner shaft may be increased by movement of said relativelyrotatable member from one position to another.

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